This lecture gives an introduction to the topic of supernova nucleosynthesis which is at the origin of almost all nuclear species that we encounter in the Universe. It starts with an overview over the relevant nuclear physics, with some emphasise on nuclear stability and nuclear reactions. The central part of the lecture is devoted to the synthesis of new elements in the interiors of stars, either during their quiescent live or during their violent explosion as supernova. The different types of supernova explosions are exposed and their key nucleosynthesis products are summarised. The lecture closes with an overview over gamma-ray line diagnostics which provides a modern tool to study supernova nucleosynthesis by the measurement of freshly produced radioactive isotopes.